Merge pull request rmosolgo#3457 from coding-chimp/source-keyword-arguments

Source keyword arguments

Author: Robert Mosolgo

lib/graphql/dataloader.rb

@@ -29,7 +29,12 @@ def self.use(schema)
 
     def initialize
       @source_cache = Hash.new { |h, source_class| h[source_class] = Hash.new { |h2, batch_parameters|
-          source = source_class.new(*batch_parameters)
+          source = if RUBY_VERSION < "3"
+            source_class.new(*batch_parameters)
+          else
+            batch_args, batch_kwargs = batch_parameters
+            source_class.new(*batch_args, **batch_kwargs)
+          end
           source.setup(self)
           h2[batch_parameters] = source
         }
@@ -43,8 +48,15 @@ def initialize
     # @param batch_parameters [Array<Object>]
     # @return [GraphQL::Dataloader::Source] An instance of {source_class}, initialized with `self, *batch_parameters`,
     #   and cached for the lifetime of this {Multiplex}.
-    def with(source_class, *batch_parameters)
-      @source_cache[source_class][batch_parameters]
+    if RUBY_VERSION < "3"
+      def with(source_class, *batch_parameters)
+        @source_cache[source_class][batch_parameters]
+      end
+    else
+      def with(source_class, *batch_args, **batch_kwargs)
+        batch_parameters = [batch_args, batch_kwargs]
+        @source_cache[source_class][batch_parameters]
+      end
     end
 
     # Tell the dataloader that this fiber is waiting for data.

spec/graphql/dataloader_spec.rb

@@ -67,6 +67,20 @@ def fetch(keys)
       end
     end
 
+    class KeywordArgumentSource < GraphQL::Dataloader::Source
+      def initialize(column:)
+        @column = column
+      end
+
+      def fetch(keys)
+        if @column == :id
+          Database.mget(keys)
+        else
+          Database.find_by(@column, keys)
+        end
+      end
+    end
+
     module Ingredient
       include GraphQL::Schema::Interface
       field :name, String, null: false
@@ -149,6 +163,14 @@ def recipe(recipe:)
         recipe
       end
 
+      field :key_ingredient, Ingredient, null: true do
+        argument :id, ID, required: true
+      end
+
+      def key_ingredient(id:)
+        dataloader.with(KeywordArgumentSource, column: :id).load(id)
+      end
+
       field :recipe_ingredient, Ingredient, null: true do
         argument :recipe_id, ID, required: true
         argument :ingredient_number, Int, required: true
@@ -456,6 +478,26 @@ def database_log
     assert_equal expected_log, database_log
   end
 
+  it "works with sources that use keyword arguments in the initializer" do
+    query_str = <<-GRAPHQL
+    {
+      keyIngredient(id: 1) {
+        __typename
+        name
+      }
+    }
+    GRAPHQL
+
+    res = FiberSchema.execute(query_str)
+    expected_data = {
+      "keyIngredient" => {
+        "__typename" => "Grain",
+        "name" => "Wheat",
+      }
+    }
+    assert_equal expected_data, res["data"]
+  end
+
   class UsageAnalyzer < GraphQL::Analysis::AST::Analyzer
     def initialize(query)
       @query = query